Classifications

• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23B—PRESERVATION OF FOODS, FOODSTUFFS OR NON-ALCOHOLIC BEVERAGES; CHEMICAL RIPENING OF FRUIT OR VEGETABLES
  • A23B2/00—Preservation of foods or foodstuffs, in general
  • A23B2/10—Preservation of foods or foodstuffs, in general by treatment with pressure variation, shock, acceleration or shear stress
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23B—PRESERVATION OF FOODS, FOODSTUFFS OR NON-ALCOHOLIC BEVERAGES; CHEMICAL RIPENING OF FRUIT OR VEGETABLES
  • A23B2/00—Preservation of foods or foodstuffs, in general
  • A23B2/70—Preservation of foods or foodstuffs, in general by treatment with chemicals
  • A23B2/704—Preservation of foods or foodstuffs, in general by treatment with chemicals in the form of gases, e.g. fumigation; Compositions or apparatus therefor
  • A23B2/708—Preservation of foods or foodstuffs, in general by treatment with chemicals in the form of gases, e.g. fumigation; Compositions or apparatus therefor in a controlled atmosphere, e.g. partial vacuum, comprising only CO2, N2, O2 or H2O
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23B—PRESERVATION OF FOODS, FOODSTUFFS OR NON-ALCOHOLIC BEVERAGES; CHEMICAL RIPENING OF FRUIT OR VEGETABLES
  • A23B2/00—Preservation of foods or foodstuffs, in general
  • A23B2/70—Preservation of foods or foodstuffs, in general by treatment with chemicals
  • A23B2/704—Preservation of foods or foodstuffs, in general by treatment with chemicals in the form of gases, e.g. fumigation; Compositions or apparatus therefor
  • A23B2/721—Preservation of foods or foodstuffs, in general by treatment with chemicals in the form of gases, e.g. fumigation; Compositions or apparatus therefor in a controlled atmosphere comprising other gases in addition to CO2, N2, O2 or H2O
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23V—INDEXING SCHEME RELATING TO FOODS, FOODSTUFFS OR NON-ALCOHOLIC BEVERAGES AND LACTIC OR PROPIONIC ACID BACTERIA USED IN FOODSTUFFS OR FOOD PREPARATION
  • A23V2002/00—Food compositions, function of food ingredients or processes for food or foodstuffs

Definitions

• the present invention relates to a method for the hot preservation of food, having the features described in the preamble to Claim 1, which is the principal claim.
• the food may be cooked or pre-cooked, but, in some cases, it may be both cooked and preserved as specified by the method .
• the invention relates to the specific field of preserving over a period of time foods and provisions which have been subjected to cooking or pre-cooking, and is applicable in particular, but not exclusively, to food preserving processes used in the provision of public catering, for example in restaurants, canteens and the like, supermarkets, public catering services and military catering .
• the preserving of cooked or pre ⁇ cooked food takes place in various ways, according to the required preservation time.
• freezing is carried out if the required preservation time is reckoned in days or weeks .
• the food is refrigerated (at 4°C, for example) if the preservation time is a few days .
• the food is preserved in the hot state in equipment for maintaining the temperature (at 70°C, for example) if the required time is several hours.
• preserving is carried out at ambient temperature if the cooked food is to be consumed immediately or within a few hours of cooking.
• a first limitation is due to the fact that the food has to be brought to a relatively high temperature before serving, and therefore considerable periods of time are required .
• the organoleptic characteristics of the food are also frequently compromised to a greater or lesser extent, as a result of thermal and mechanical stresses (particularly during the freezing process) and because of bacterial action, which is reduced but not eliminated.
• the cold chain also has a high specific energy requirement for the three essential steps of temperature reduction, preserving, and regeneration at the serving temperature.
• the preservation time is also limited to a few hours because, at these temperatures, bacterial action and the degradation of the organoleptic characteristics is very rapid.
• the ideal preservation time is several days, for example in catering, where the cycle is typically weekly.
• the main object of the invention is to provide a method for the hot preserving of cooked or pre-cooked food, designed to prevent or retard microbial, physical and chemical changes in the cooked or pre-cooked food while keeping the organoleptic characteristics unaltered or improved over preservation times of about one week or more .
• Yet another object is to provide a method for the hot preservation of food which requires a limited amount of specific energy for the whole process, from cooking to serving .
• Yet another object is to cook the food at low temperature and to keep it in the same apparatus as that in which it was cooked.
• hot in the present context denotes temperatures above 57.2°C (135°F) as indicated in the US FDA Food Code, in order to prevent deterioration of the food due to bacterial action.
• the food having undergone a step of cooking or pre-cooking in a suitable cooking unit or directly in the apparatus used for hot preservation at the temperatures specified for this preservation, is subjected to a preservation step in which the cooked or pre-cooked food is confined in a preserving chamber.
• this preserving chamber solely for preserving the food which has been cooked or pre-cooked in other apparatus, or to use it for both the cooking and the preservation steps, in the case of certain foods .
• the preserving chamber is a chamber with a controlled atmosphere, and the preserving method, according to a main combination of characteristics, provides for keeping the food in the chamber, at a selected predetermined temperature in the range from 57.2°C to 90 °C, for a preservation time of more than at least 24 hours, the partial oxygen pressure in this chamber being kept below 10 kPa.
• the preservation temperature is chosen to have a predetermined value in the range from 58 °C to 72 °C.
• the choice of the value within the aforesaid range may also depend on the type of food to be preserved (for example, the type of meat, fish or vegetable) .
• vegetables are better preserved at a temperature a few degrees below that specified for the preservation of meat.
• the bacterial action on the food is substantially negligible, and the degradation of the organoleptic characteristics is caused primarily by:
• the physical process which may have the greatest effect on the organoleptic characteristics of the food is the process brought about by the evaporation of water and its diffusion into the food, particularly on the surface. It may happen, for example, that the surface loses its original crispness during preservation, and a fast heat treatment at high temperature is required to restore it before serving.
• This heat treatment may also be provided in the method according to the invention, since it has no effect on the principal characteristics of the method.
• Chemical transformation reactions other than oxidation affecting compounds in the food are very slow at the aforesaid preservation temperatures and therefore have a negligible effect. Indeed, in some cases, such as that of meat described as "lean", that is to say high in connective tissue, preservation for several days at these temperatures improves the quality, because the gelatinization of the collagen protein is promoted, thus increasing the tenderness of the meat.
• the elimination or reduction of the oxygen concentration in the controlled atmosphere chamber in which the food is preserved is therefore essential if preservation times of several days are to be achieved.
• non-oxidizing gas for example nitrogen and/or water vapour and/or carbon dioxide and/or nitrogen oxide.
• Nitrogen has the advantage of being chemically neutral in relation to the cooked food, inexpensive and easily obtained; water vapour can be produced before or after the introduction of the nitrogen into the chamber in which the food is preserved.
• the non-oxidizing gas may be obtained, for example, from cylinders, or as the result of the combustion of air with hydrocarbons or other carbon compounds, generating a mixture of gases which typically contain nitrogen, carbon dioxide and water vapour. Additionally, humidification may be carried out before the non-oxidizing gas is introduced into the chamber, to prevent the drying of the food to be preserved.
• the preserving chamber with a controlled atmosphere is kept at atmospheric pressure and at a predetermined temperature in the range from 57.2°C to 90°C, preferably from 58°C to 72°C, for a preservation time of more than at least 24 hours, the partial oxygen pressure in the chamber being kept below 10 kPa, by at least partially replacing the oxygen present in the chamber with nitrogen which is introduced into the chamber.
• the nitrogen may, for example, be introduced into the preserving chamber by being supplied from a cylinder.
• the air present in the chamber is composed solely of oxygen and nitrogen in their usual percentages by weight, namely 21% and 79% respectively, and that the atmospheric pressure is, in a first approximation, equal to about 100 kPa
• the partial pressures of these gases may be considered to be 21 kPa (oxygen) and 79 kPa (nitrogen) respectively.
• the oxygen is partially replaced with nitrogen by introducing the latter into the preserving chamber until the respective concentrations of the oxygen and nitrogen tend towards 10% oxygen and 90% nitrogen, thereby creating respective partial pressures of 10 kPa for the oxygen and 90 kPa for the nitrogen.
• the replacement process which, as mentioned above, takes place substantially at atmospheric pressure, may continue until the desired value of partial oxygen pressure (less than 10 kPa) is reached.
• the following operations may also be provided:
• a chemical process reaction
• a physical process e.g. absorption or adsorption
• liquid water and/or water vapour may be added at the start of the preservation time, for example simultaneously with the introduction of non-oxidizing gas, so that the conditions of psychrometric equilibrium are reached rapidly and the evaporation of water from the surface of the food is prevented .
• the optimal oxygen concentration When the optimal oxygen concentration has been defined, it is important that it should not be exceeded over time, or, in any case, that it is kept within a predetermined range; otherwise the velocity of the oxidation process will increase, thereby advancing the degradation of the organoleptic characteristics.
• oxygen is released from the food at such a rate that it increases the concentration in the preserving environment (which is a closed environment having a volume adapted to that of the food to be preserved) . This increase is frequently non-negligible, and requires a restoration of the initial concentration conditions. Therefore the preserving apparatus should preferably be provided with a system for restoring the initial oxygen concentration.
• This system for restoring the initial oxygen concentration may be, for example:
• the method of the invention may also be applied to the cooking and preservation of food; that is to say, the food is cooked in the preserving chamber itself.
• This relates, in particular, to foods that are cooked at relatively low temperatures (for example, many varieties of fish and certain types of vegetables) .
• the food can be kept there for several more days, by following the procedures described for cooked or pre-cooked food (with control of the oxygen concentration and the temperature, and of the humidity if necessary) .
• the cooking may take place at the predetermined preservation temperature or at another temperature, in the presence of oxidizing gases or otherwise, and with or without the introduction and/or production of water vapour.
• the cooking temperature may be suitably set at a higher level than the preservation temperature established subsequently in the preserving chamber.
• a principal advantage of the hot preserving method according to the invention is that cooked or pre-cooked food can be preserved for preservation times of more than 24 hours, and conveniently for several days, while the organoleptic characteristics of the food are maintained and the microbial, physical and chemical changes in the cooked or pre-cooked food are prevented or retarded, with the advantage that the quality of the surface characteristics of the food can be restored rapidly before serving, thus reducing to a few minutes the time required to serve the food from the preserving apparatus to the table, and with the further advantage of limiting the specific energy required for the preservation process.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Wood Science & Technology (AREA)
• Zoology (AREA)
• Chemical & Material Sciences (AREA)
• Food Science & Technology (AREA)
• Polymers & Plastics (AREA)
• Food Preservation Except Freezing, Refrigeration, And Drying (AREA)
• Meat, Egg Or Seafood Products (AREA)
• Packages (AREA)
• General Preparation And Processing Of Foods (AREA)

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Publications (1)

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Citations (9)

Family Cites Families (17)

• 2013
  • 2013-08-07 IT IT000228A patent/ITPD20130228A1/it unknown
• 2014
  • 2014-07-28 JP JP2016520149A patent/JP6184595B2/ja active Active
  • 2014-07-28 US US14/910,097 patent/US10426182B2/en active Active
  • 2014-07-28 CN CN201480044802.0A patent/CN105722404B/zh active Active
  • 2014-07-28 RU RU2016107835A patent/RU2659401C2/ru active
  • 2014-07-28 EP EP14744551.4A patent/EP3030095B1/en active Active
  • 2014-07-28 WO PCT/EP2014/066176 patent/WO2015018682A1/en not_active Ceased
  • 2014-07-28 PL PL14744551T patent/PL3030095T3/pl unknown
  • 2014-07-28 ES ES14744551.4T patent/ES2627177T3/es active Active

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